基于流体结构互动理论的水工平面闸门流激振动机理研究

The fluid-induced vibration and the vortex-induced vibration mechanism of hydraulic plane gate will be investigated by using a combination of theoretical analysis, numerical simulation and model test means. The direct numerical simulation method combined with the nonlinear system analysis will be employed to study the fluid dynamics behaviour such as flow bifurcation, structural instability and transition process of the vortex structure in the slot. The improved large-eddy simulation method will be adopted to numerate the unsteady pressure fluctuation and turbulence characteristics of the gate orifice flow. Based on establishing the gate structure control equations, the Navier-Stokes equations of arbitrary Lagrangian-Eular description and the coupling interface conditions, the numerical solution of fluid and structure dynamics equations will be conducted respectively by one-way and strongly two-way fluid-structure coupling modes. the hydraulic test models will be built. the pressure fluctuation of gate orifice flow and the dynamics parameters of gate structure will be measured. A innovative computing mode for the plane gate hydraulic exciting force may be established based on the parallel algorithm. The methods and results will help to improve the dynamics computing accuracy and the prediction level of the plane gate fluid-induced vibration, to reveal the mechanism of fluid-induced vibration and the vibration induced by the vortexes in the slot, and to provide an important reference basis for mitigating and avoiding the gate vibration.

采用理论分析、数值模拟和模型试验手段，深入研究水工平面闸门的流激振动和门槽涡流激振特性。采用直接数值模拟方法并结合非线性系统分析，研究门槽内部涡结构分岔、失稳和暂态过程等流体动力学行为；采用改进的大涡模拟方法，分析计算非定常过闸水流的压力脉动和紊流特性；建立闸门结构控制方程、基于任意拉格朗日-欧拉描述的N-S流体控制方程和耦合界面边界条件，分别采用单向耦合和双向强耦合模式数值求解流体与结构动力学方程。制作水工试验模型，测量闸门结构的动力学参数和过闸水流的压力脉动。基于并行算法，建立平面闸门水力激振力新的计算模式，提高平面闸门流激振动的动力学计算精度和预测水平，揭示平面闸门非线性流激振动和门槽涡流激振机理，为水工平面闸门的减振和避振提供重要参考依据。

平面闸门流激振动在水利工程实践中经常发生，但其激振机理广泛而复杂。从流体结构互动理论出发，基于数值模拟、模型试验和理论分析，深入研究了淹没出流条件下水工平面闸门振动的结构自振特性、激励源水力特性以及流固耦合振动响应规律。根据空间点源汇及偶极子基本解理论，建立了水体附加质量模型，分析了水体附加质量对平面闸门自振特性的影响。采用数值模拟并结合非线性系统分析，揭示了剪切驱动涡流结构的流型分岔、稳态和暂态等演化特征，考察了门槽体形参数对湍流场的低压效应并获得了门槽体形参数较优取值范围；采用大涡模拟方法和流体体积模型相结合模拟了非定常淹没闸孔出流的水力特性，捕获到门槽内部、闸门底缘、闸门下游漩涡共存的完整流动结构。建立了结构控制方程、任意拉格朗日-欧拉描述的流体大涡运动方程、耦合界面条件以及动网格模型；分别进行了单向和双向流固耦合数值求解，获得了平面闸门在典型工况下的应力、变形分布规律以及闸门上典型测点的振动响应时程。组建了平面闸门流固耦合振动同步测试系统，分析了过闸水流不同测点的脉动压力分布以及闸门下游流场中的漩涡分布，获得了闸门振动位移随潜流比、闸下平均流速以及闸门开度比的变化规律。进行了数值模拟和模型试验的结果对比分析，考察了门槽内部漩涡对闸门附近流场和闸门振动的影响，明确了湍流的动水压力脉动及闸门附近多处涡流的存在和演化是诱导闸门振动最根本的原因。该项目研究有利于深入理解平面闸门的流激振动机理，为平面闸门的减振和避振提供了重要的参考依据。